Roller tappet for poppet valves and method of making the same



June 21, 1927. R JARDINE 33,331

ROLLER TAPPBT FOR POPPET VALVES AND METHOD OF MILKING THE SAME Filed Sept. 9, 1922 Patented June 21, 1927,

UNITED STATES 1,633,331 PATENT OFFICE.

ROBERT .TARDiNE, or CHICAGO, ILLINOIS, ASSIGNOR T0 RICH moor. COMPANY, or CHICAGO,1ILLINOIS, A CORPORATIQN or MAINE.

ROLLER TAPPET FOR POPPET VALVES AND METHOD OF MAKING THE SAME.

Application filed September 9, 1922. Serial No. 587,246.

The invention relates to valve tappets for internal combustion engines having poppet valves, and especially to those valve tappet-s which are equipped with a roller for coaction with the valve-operating cam.

The object of the invention is to provide a roller valve tappet of improved form, having particular reference to reducing, the weight and inertia of the tappet, while maintaining a suitable wall thickness at the place where the roller is to be supported, and without substantial departure from the usual exterior shape and dimensions. The method of producing the tappet in the im- F proved form at relatively low cost, through the employment of a few simple manufacturing operations, is also an object of the invention. I

In the accompanying drawings:

Fig. 1 is a side elevation of a blank from which the shell and stem of the improved tappet may be produced;

Fig. 2 is an end view of the blank trated in Fig. 1; g

Fig. 3 is a central longitudinal sectional view, and Fig. 4 an end view similar to Fig. 2, both showing the form of the blank after the initial steps in the manufacture of the illus improved tappet have been performed thereon;

Figs. 5 and 6 are similar to Figs. 3 and 4, respectively, but show the form of theblank at another stage in the manufacture of the tappet;

Fig. 7 is a central longitudinal sectional view of the completed tappet shell and stem; Fig. 8 is an end view of the tappet shell; and I I Fig. 9 is a side elevation of the completed tappet with the form of cooperatmg cam and the'corresponding cam shaft indicated by dotted lines.

Owing to the rapidity with which the poppet valves of an internal combustion engine are operated, and the importance of their responding easily and lnstantly to the opening and closing impulses of the valve cams and springs, it is of the greatest importance that both the valves and the associated tappets, as 10 (Fig. 9) should be as light in weight as possible, consistent with the other requirements of the service to which they are subjected. Furthermore, since the bod or shell, as 11, of the tappet should be 0 reasonable size for sliding movement in the associated bearing (not shown) without binding or excessive wear, it is likewise important that the said tappet shell should have the thinnest possible walls consistent with strength in all parts where a greater" wall thickness is not required for other reasons.

On the other hand, when the tappet is equipped with a roller, as 12, for engagement with the valve operating cam, as 13, it is necessary to form the walls of the shell 11 with thickened portions, as 14, 15, to pro vide suitable bearings for the pin, as 16, upon which the roller 12 is mounted. These thickened portions, as 14, 15, of the walls of the tappet shell must not only be at opposite sides of the shell and near the open end thereof, but to avoid interference with the movement of the tappet in its bearing the increased thickness must be provided upon the inside rather than the outside of the shell. Likewise, to provide clearance for the endsof the pin 16 the said inward extensions or additions to the walls of the shell must be sufficiently great to permitthe formation of the shell with flattenedportions, as 18, 19, upon the outside of the same, while still retaining the increase of wall thickness desired at these points. It follows that while the bore, as 19, of the shell 11 may be, and referably is, uniform throughout except or the inward extension and flattening of the walls upon two sides of the shell adjacent the open'end or mouth, as 20, thereof, the irregular form of the shell at its mouth is such as to prevent the formation of the bore by the methods usually employed for that purpose.

In carrying out the invention the shell 11 and its stem, as 21, may be formed integral from a solid blank 22 (Figs. 1 and 2) preferably equal in length to the combined length of the shell and, stem, andof uniform diameter throughout, except that it is formed with a pair of rounded lateral bosses 23, 24, which extend along opposite ameter and length of the bore of the finished shell 11. If the stem 21 of the finished tappet 10 is to be tubular and threaded, as shown, the blank may also be drilled and threaded from the other end thereof, at this time, in which case it will appear as in Figs. 3 and 4:. v

The next operation upon the blank 22 is to forge the same to force the bosses 23, 24, 'in wardly and give the blank a uniform exterior diameter throughout its length. In this manner the thickened portions of the walls of the shell, previously extending upon the outside of the blank, as in Figs. 3 and 4,

' because of the provision of the bosses 23, 24,

and the drilling of the blank to a uniform bore, are made to project wholly within the bore of the shell, with. fiat inner surfaces where they become the said thickenedportions it, 15, of the walls of the shell in which the roller pin 16 is to be supported.

ll hen'the shell 11 has been developed to the form illustrated in Figs. 5 and 6, it may be completed by the usual operations, including turning down the stem 21, drilling the thickened portions 14:, 15, and producing the flattened surfaces 17, 18, upon the outside, heat treatment of the shell and the provision of a highly polished and very accurate bearing surface upon the outside of the body of the shell, throughout the full length of the same. Finally the roller 12 and pin 16 will be fixed in place.

I claim as my invention 1. The method of making a cylindrical valve tapp'et shell without exterior projections but having a thickened wall portion at one side which consists in longitudinally drilling a cylindricalblank having a lateral boss, pressing the said boss inwardly to'form a shell of uniform diameter without .increasing its length, flattening the sides of said shell, and thereafter perforating the flattened sides. I

2. Thefinethod of making a cylindrical valve tappet shell without exterior projections but having an open end and a thickened side wall adjacent the open end of the shell, 'which consists in longitudinally drilling a cylindrical blank having a lateral boss adjacent the end from which it is drilled, pressing the said boss, inwardly to form ashell of uniform diameter without increasing its length, flattening the open end of said shell, and thereafter securing a pin ameter having oppositely projecting lateral bosses at the end thereof from which it is drilled, pressing the said bosses inwardly without lengthening said shell to form the same of'unifo'rm diameter throughout its length, flattening the end of said shell at the thickened portions, and thereafter per forat-ing the flattened port-ions. V y 4. A roller valve tappet shell having an open end, an exterior cylindrical bearing surface and a'pair of parallel flat sidewall sections adjacent the open end of the shell not projecting outwardly beyond the said cylindrical bearing surface, the walls of said shell being thickened adjacent the flat side wall sections, and provided with trans verse openings therethrough, a pivot pin secured in said openings, and a roller journaled on said pin.

5. A roller valvetappet shell having an open end, an exteriorcylindrical bearing surface and a pair of'parallel flat side wall sections adjacent the open end of the shell not projecting outwardly beyond the said cylindrical bearing surface but thicker than i the walls of the shell in-other parts thereof and integral therewith, the exterior diameter of said shell being greater than the distance between the exterior surfaces of said flatside wall sections. g

'6. A roller valve tappe't member having hollow body portion terminating at one end in a pair of flat side wall sections having pm. e I,

- ROBERT JARDINE,

alined apertures therethrough, said sections 1 

